Contractor shall test feasibility and cost-effectiveness of 4 approaches to hypertension control in the work setting. The 4 approaches are: Controlled services (initial education, screening, referral, rescreening); Modified follow-up (semi-annual follow-ups for referrals); Full follow-up (intensive follow-up and education of individuals and follow-up of attending physician); On-site treatment. Contractor will document program outcomes, analyze data by making comparison across the 4 sites (improvement in adequacy of blood pressure control, reduction in health-related costs over project period, and cost of each program), and develop cost-benefit estimates for each approach.